Moron, the Little 3D Printer

Wait.  Did I mean to say "More on the Little 3D Printer"?

No.  No I did not.

My 101Hero has no idea what it's extruder temperature actually is.

The highest possible indicated extruder temperature is 208C. That's as hot as it goes when I set a temperature of 208 or higher.

The internal (firmware) low temperature cutoff is set for about 178C, meaning you get a "Low temperature extrusion prevented" message when trying to print at that temperature or lower.

The Ziro gold PLA filament I'm using has a recommended temperature range of 190C-220C, a range of 30C.  The test prints for the 101Hero all seem to use a temperature of 203C, and with the Ziro filament, the test prints I tried all printed with a dull, sandy finish.

From what Google tells me, dull PLA means over-temperature, essentially cooking it into a runny, stringy mess.

By experimentation, I found that a setting of 185C yields much better-looking prints.

I wanted to understand the accuracy of the temperature indication on my 101Hero 3D printer.  So I chose the Customizable Temperature Calibration Tower from Thingiverse, configured it to cover the range from 208C down to 164C by steps of 4C in a height of 96 mm, which is 12 steps of 8 mm each.

I downloaded the customized model and installed the "Vary Temperature With Height" Cura plugin that came with it.  I then opened the STL file in Cura, selected the plugin and set its values to match the model configuration.

I set the layer thickness to 0.18", with no infill and no top, with only a one-layer base, with a wall thickness of 0.80 (2 layers), and with a starting temperature of 208C.

Then I saved the GCode and started the print.  Which abruptly ended when it tried to print the step at 176C.  Because that value is less than 178C. So instead of printing, it generated countless "low temperature" error messages.

I aborted the print, selected Start/End-GCode -> end.gcode, then inserted an "M302" command to be the next-to-last command in the file.  This command disables the "low extrusion temperature" logic.

I then saved the GCode again and restarted the print, with the following results:

The temperature scale, with hot on the left (bottom) and cold on the right (top).

The legend side, which says: "101Hero / Ziro Gold PLA"

The step test side.

The smooth side.

First, it is important to note that all layers in this test were well bonded together: I tried twisting the tower, and none of the layers separated.  This could be due to having a 2-layer wall - perhaps a single-layer wall would have been a better test, but I wanted to allow lots of time for the temperature to settle early in each step.

Update: I did a single-wall print, and it was very similar to the double-wall, but easier to test the wall quality. Again it was remarkably consistent, with the 184C region maybe being slightly superior.

It is clear that the left end is rough and grainy, a sign of overheated PLA filament. The graininess is not present at (indicated) temperatures of 192C and below.  Ideally, the coolest layer of a temperature tower should show some blobiness due to partial filament melting.  This tells me that I need to repeat the test down to even lower (indicated) temperatures.

The step test side looks best at 184C, though it really doesn't look bad in any of the other steps.  This is the only clue I have that my guessed temperature of 185C is anywhere close to ideal.

If we say an indicated temperature of 185C is near the middle of the range given on the spool label, then the actual extruder temperature is closer to 205C, an error of 20C!

Bottom line, the indicated temperature reading of my 101Hero is insane.

Which doesn't really matter: It's just a number!  So long as I know the right number to use for my prints, it's not a problem.

The lesson here is to always print a temperature tower for each new filament.

Next test: A Speed Calibration Tower.  I've been printing everything at a rate of 10 mm/s because that's what most users have recommended.  But how fast can the 101Hero go, and how bad does it get with increasing speed?